This paper studies a New Keynesian model in which monetary policy may switch between regimes. We derive sufficient conditions for indeterminacy that are easy to implement and we show that the necessary and sufficient condition for determinacy, provided by Davig and Leeper, is necessary but not...

A multivariate model, identifying monetary policy and allowing for simultaneity and regime switching in coefficients and variances, is confronted with U.S. data since 1959. The best fit is with a model that allows time variation in structural disturbance variances only. Among models that also...

This paper presents a theory of the monetary transmission mechanism in an old-Keynesian model with multiple equilibrium unemployment rates. The model has two equations in common with the new-Keynesian model; the optimizing IS curve and the policy rule. It differs from the new-Keynesian model by...